As shown in FIG. 1, during display using an active matrix Organic Light Emitting Diode (OLED), various rows of scan lines and various columns of data lines intersect to form an active matrix. Generally, various rows of gating diodes are opened in turn by using a progressive scanning method to apply voltage on the data lines to pixel driving diodes, which convert the voltage into current to drive the OLED to emit light for display.
A driving circuit for the scan lines is typically implemented by using shift registers. The shift registers may be divided into dynamic shift registers and static shift registers in terms of categories. The dynamic shift registers generally have a relatively simple structure, and need a few of Thin Film Transistors (TFTs), but consume large power and operate at a limited frequency bandwidth. The static shift registers need more TFT devices, but operate at a larger bandwidth and consumes less power. With the increase of a size of a display panel, a row scan driving circuit is generally implemented by using TFT transistors made of amorphous silicon (a-Si) or polycrystalline Si (p-Si), and is directly manufactured on the panel. This may eliminate interconnection with a peripheral driving circuit, and reduce the size and cost. The row scan driving circuit which is designed based on a panel has low requirements for the speed, but needs a compact structure and a small occupation area. As a result, the row scan driving circuit is often implemented by using dynamic shift registers. In addition, the conventional shift register which is designed by using a Positive channel Metal Oxide Semiconductor (PMOS) transistor and an N-Mental-Oxide-Semiconductor (NMOS) transistor is relatively complex in terms of process realization, and leads to a high cost (the shift register generally needs to include 7-9 mask plate layers) and large transient current. Therefore, the panel based design typically utilizes a dynamic circuit which merely uses an NMOS or a PMOS. In consideration of the performance of the shift register, it needs to comprehensively consider factors such as an operating voltage, power consumption, reliability, and an area. However, with the gradual increase of the size of the panel, the power consumption and the reliability have become more important performance parameter indexes. Generally, due to material and a film thickness, both threshold voltages Vth (i.e., absolute values thereof) of thin film transistors based on an a-Si process and a low temperature p-Si process are large, which results in a large operating voltage and high power consumption of the shift registers designed by using the thin film transistors.
The exiting Gate driver on Array (GOA) of an array plate is a logic circuit which generates a single-pulse waveform. As shown in FIG. 2, in order to avoid non-uniformity in the display of the panel due to a shift of the Vth, an OLED pixel structure is generally a pixel circuit having a function of internal threshold voltage compensation. When dual pulses are input into the exiting GOA circuit, a simulation result illustrated in FIG. 3 may be generated.
It can be seen from the simulation result in FIG. 3 that if a dual-pulse waveform is input into the existing GOA, the existing GOA is unable to output a dual-pulse waveform. Specifically, a waveform at a point Q cannot be pulled up when a second pulse arrives, and thus the point Q cannot operate normally, which results in the GOA circuit being unable to achieve a function of outputting a multi-pulse waveform.